Add items to crontab: Difference between revisions

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== Background ==
== Background ==


==== Skills required ====
See [http://en.wikipedia.org/wiki/Cron Cron on Wikipedia]


You must be able to connect to your qnap using telnet and edit using vi.
=== Skills required ===


==== crontab ====
You must be able to connect to your QNAP device using [[How_to_SSH_into_your_QNAP_device|SSH]] and edit using a text editor such as [[Using_vi|vi]] or nano.


The crontab can be used to execute tasks (scripts) based on a reoccuring schedule; by default the crontab is used, for example, to restart the webserver during the night.
=== crontab ===


To view the content of the crontab, login to your qnap using telnet and type:
The crontab can be used to execute tasks (scripts) based on a recurring schedule. The crontab is used, for example, to restart the webserver during the night.
 
To view the content of your crontab, login to your QNAP via SSH and type:
<pre>crontab -l
<pre>crontab -l
</pre>
</pre>
Line 15: Line 17:
You will see a (small) list of crontab entries.
You will see a (small) list of crontab entries.


Editing the crontab is also easy, on the console type:
<pre>crontab -e</pre>


The crontab will be shown inside a vi session. Edit the crontab as you wish.


Once you have edited the crontab, execute the following to activate it:
== Standard crontab jobs ==
<pre>/etc/init.d/crond.sh restart</pre>


See [http://en.wikipedia.org/wiki/Cron Cron on Wikipedia]
The following table contains the standard QNAP jobs that run on schedules.


== Stock crontab jobs ==
This list is by no means complete. Jobs may depend on the firmware version, start times may vary. If you find a job on your QNAP, that is missing from the table, add it. The list could help to identify unwanted jobs that regularly wake up your harddisk(s).


When using crontab -l on a default QNAP, QNAPs has some default crontab jobs.
{| cellspacing="1" cellpadding="1" border="1" width="100%"
 
Usually you will want to know, what default jobs are running on the QNAP based on schedule.
 
The following table is meant to bring some light into those built-in jobs.The list is by no means complete, jobs may depend on the firmware version, start times may vary. If you find a job on your QNAP, that is missing in the table, add it. The list could help to identify unwanted jobs on the QNAP&nbsp;that regularly wake up your harddisk(s).
 
{| width="100%" cellspacing="1" cellpadding="1" border="1"
|-
|-
! scope="col" | Default Time<br/>
! scope="col" | Default Time<br/>
Line 39: Line 31:
! scope="col" | Explanation<br/>
! scope="col" | Explanation<br/>
|-
|-
| 0 4 * * *
| 0 4 * * *<br/>
| /sbin/hwclock -s
| /sbin/hwclock -s
| [http://linux.die.net/man/8/hwclock http://linux.die.net/man/8/hwclock]<br/>
| [http://linux.die.net/man/8/hwclock http://linux.die.net/man/8/hwclock]<br/>
Line 47: Line 39:
| vs_refresh is for share folder space usage calculation (for Network Share Management)<br/>
| vs_refresh is for share folder space usage calculation (for Network Share Management)<br/>
|-
|-
| 0 3 * * 0
| 0 3 * * 0<br/>
| /etc/init.d/idmap.sh dump
| /etc/init.d/idmap.sh dump
| related to SAMBA Active Directory configuration. Used if security is set to ADS.<br/>
| related to SAMBA Active Directory configuration. Used if security is set to ADS.<br/>
|-
|-
| 0 3 * * *
| 0 3 * * *<br/>
| /sbin/clean_reset_pwd
| /sbin/clean_reset_pwd
| (unclear) might be the new behaviour of the network recycle bin (purging files after a certain amount of days)<br/>
| (unclear) might be the new behaviour of the network recycle bin (purging files after a certain amount of days)<br/>
|-
|-
| 0-59/15 * * * *
| 0-59/15 * * * *<br/>
| /etc/init.d/nss2_dusg.sh
| /etc/init.d/nss2_dusg.sh
| is a job of the Surveillance Station<br/>
| is a job of the Surveillance Station<br/>
Line 94: Line 86:




== Method 1: /etc/config/crontab ==
== Adding entries at the command-line ==
Here are a couple of examples that append new entries to the crontab file:<pre>echo "1 4 * * * /share/custom/scripts/custom1.sh" >> /etc/config/crontab
echo "40 5 * * * /share/custom/scripts/custom2.sh" >> /etc/config/crontab</pre>


Edit /etc/config/crontab directly, then tell the cron service to reload the crontab. These changes will persist past a reboot so '''be careful!'''


Here is an example which assumes you are ssh'd / telnet'd into your nas (as admin).
<pre>echo "1 4 * * * /share/custom/scripts/custom1.sh" &gt;&gt; /etc/config/crontab
echo "40 5 * * * /share/custom/scripts/custom2.sh" &gt;&gt; /etc/config/crontab
crontab /etc/config/crontab</pre>


== Method 2: autorun.sh ==
== Modifying entries ==


''Some peoples have reported this method as the working method and others have reported that this does not. Perhaps it is an outdated way to add cron jobs.''
'''<span style="color:red">Do NOT edit crontab the usual way!</span>'''


<br/>Editing the crontab directly using 'crontab -e' as described above is possible on the QNAPs and it will function as expected. However as soon as your QNAP is restarted, you will be surprised to learn that all your custom entries will be gone from the crontab!
On a desktop or server distribution, you would edit a user's crontab with:
<pre>crontab -e</pre>


<br/>To prevent the loss of your work, use [[Autorun.sh|Autorun.sh]] or [http://www.qnap.box.cx/ AutoRunMaster] and a custom script for changing the crontab:
However, due to the way the QNAP firmware updates crontab, it will be '''overwritten''' on the next reboot. Obviously, you want your automation to survive reboots, so edit the crontab file directly with your text editor:
<pre>#!/bin/sh
<pre>vi /etc/config/crontab</pre>
# location: /share/custom/scripts/contab.sh
# script name: crontab script
# purpose: add entries to the crontab, which will survive a QNAP reboot
# designed for Qnap TS-201
tmpfile=/tmp/crontab.tmp


# read crontab and remove custom entries (usually not there since after a reboot
or
# QNAP restores to default crontab:
<pre>nano /etc/config/crontab</pre>
crontab -l | grep -vi "custom1.sh" | grep -vi "custom2.sh" &gt; $tmpfile


# add custom entries to crontab
echo "1 4 * * * /share/custom/scripts/custom1.sh" &gt;&gt; $tmpfile
echo "40 5 * * * /share/custom/scripts/custom2.sh" &gt;&gt; $tmpfile


#load crontab from file
crontab $tmpfile


# remove temporary file
== Restart the daemon ==
rm $tmpfile


# restart crontab
When you're done, reload the crontab file and restart the cron daemon:
/etc/init.d/crond.sh restart
<pre>crontab /etc/config/crontab && /etc/init.d/crond.sh restart</pre>
</pre>


Make sure your script is called when the qnap is started by adding it to [[Autorun.sh|Autorun.sh]] or by using [http://www.qnap.box.cx/ AutoRunMaster]




== Notes ==


== Method 1 bis:&nbsp; /etc/config/crontab, load and restart&nbsp; ==
Don't forget to make your scripts executable! Otherwise they will silently fail! You tested your script, right?
<pre>chmod +x filename.sh</pre>


In a post on&nbsp;[http://forum.qnap.com/viewtopic.php?f=144&t=32519&p=253371#p253371 http://forum.qnap.com/viewtopic.php?f=144&t=32519&p=253371#p253371]&nbsp;Micke writes&nbsp;:
Don't bother with that kind of script at all. Whenever you add a custom entry then follow this procedure
<blockquote>1. Edit /etc/config/crontab and add your custom entry.<br/>2. Run '/usr/bin/crontab /etc/config/crontab' to load the changes.&nbsp;<br/>3. Restart cron, i.e. '/etc/init.d/crond.sh restart'<br/></blockquote>
If you follow this procedure then the changes survive a reboot (even a firmware upgrade), i.e. no need for any script to restore them.
/Mike
PS.&nbsp;Don't forget to make your scripts executable&nbsp;! Otherwise they&nbsp;would not start!
<pre>chmod +x filename.sh</pre>


Tested on 3.6.0&nbsp;: works fine.&nbsp;
<div><span style="font-size:smaller">''These instructions have been tested on various versions of QNAP firmware from 3.6.0 onwards.''</span><br/></div> [[Category:Adding new services]]
[[Category:Adding new services]]

Latest revision as of 16:49, 12 December 2016

Background

See Cron on Wikipedia

Skills required

You must be able to connect to your QNAP device using SSH and edit using a text editor such as vi or nano.

crontab

The crontab can be used to execute tasks (scripts) based on a recurring schedule. The crontab is used, for example, to restart the webserver during the night.

To view the content of your crontab, login to your QNAP via SSH and type: 

crontab -l

You will see a (small) list of crontab entries.


Standard crontab jobs

The following table contains the standard QNAP jobs that run on schedules.

This list is by no means complete. Jobs may depend on the firmware version, start times may vary. If you find a job on your QNAP, that is missing from the table, add it. The list could help to identify unwanted jobs that regularly wake up your harddisk(s).

Default Time
 Job
 Explanation
0 4 * * *
 /sbin/hwclock -s http://linux.die.net/man/8/hwclock
0 3 * * * /sbin/vs_refresh vs_refresh is for share folder space usage calculation (for Network Share Management)
0 3 * * 0
 /etc/init.d/idmap.sh dump related to SAMBA Active Directory configuration. Used if security is set to ADS.
0 3 * * *
 /sbin/clean_reset_pwd (unclear) might be the new behaviour of the network recycle bin (purging files after a certain amount of days)
0-59/15 * * * *
 /etc/init.d/nss2_dusg.sh is a job of the Surveillance Station
10 15 * * * /usr/bin/power_clean -c 2>/dev/null  ?
4 3 * * 3 /etc/init.d/backup_conf.sh does an automatic backup of several config files in /etc/config.
0 3 * * *
 /bin/rm -rf /mnt/HDA_ROOT/twonkymedia/twonkymedia.db/cache/*
 Will clear the Twonky media cache
5 0 * * 1
 /etc/init.d/antivirus.sh scan 1
 If Antivirus is enabled, this will scan the files for viruses
0 0 * * *
 /etc/init.d/antivirus.sh archive_log
 If Antivirus report jobs are enabled
0 0 */1 * *
 /etc/init.d/antivirus.sh update_db
 If Antivirus is enabled, this will check  clamav.net for updates

 /etc/init.d/startup
 If a restart/powerof job is configured in power management

 /etc/init.d/poweroff
 If a restart/powerof job is configured in power management


Adding entries at the command-line

Here are a couple of examples that append new entries to the crontab file:

echo "1 4 * * * /share/custom/scripts/custom1.sh" >> /etc/config/crontab
echo "40 5 * * * /share/custom/scripts/custom2.sh" >> /etc/config/crontab


Modifying entries

Do NOT edit crontab the usual way!

On a desktop or server distribution, you would edit a user's crontab with: 

crontab -e

However, due to the way the QNAP firmware updates crontab, it will be overwritten on the next reboot. Obviously, you want your automation to survive reboots, so edit the crontab file directly with your text editor: 

vi /etc/config/crontab

or 

nano /etc/config/crontab


Restart the daemon

When you're done, reload the crontab file and restart the cron daemon: 

crontab /etc/config/crontab && /etc/init.d/crond.sh restart


Notes

Don't forget to make your scripts executable! Otherwise they will silently fail! You tested your script, right? 

chmod +x filename.sh


These instructions have been tested on various versions of QNAP firmware from 3.6.0 onwards.
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